Process of preparing alkylated hydroxy aromatic compounds



United States Patent PROCESS OF PREPARING ALKYLATED H YDRQXY AROMATIC COMPOUNDS Charles T. Hathaway, Berkshire, Mass., assignor to General Electric Company, a corporationof New York No Drawing. Application January 7, 1955, Serial No. 480,607

Claims. (Cl. 260-613) This invention relates to a new and improved method of preparing alkyl-substituted hydroxy aromatic compounds.

Alkylated hydroxy aromatic compounds and numerous methods for their preparation are now well known to the art. One of the more widely used methods involves the reaction of a hydroxy aromatic compound such as phenol with a long-chain chlorinated hydrocarbon in the presence of a Friedel-Crafts type catalyst, aluminum chloride being typical. For example, in one conventional method phenol can be condensed with a chlorinated wax in the presence of Friedel-Crafts catalysts, such as aluminum chloride, by proper manipulation. More specifically, phenol and chlorowax are first mixed together at a temperature of about 150 F. and anhydrous aluminum chloride added sufliciently slowly while actively stirring the mixture to avoid violent foaming.

Unexpectedly, I now have found that one of the major disadvantages of prior processes, namely, excessive foaming, may be eliminated by the simple procedure of first mixing the Friedel-Crafts catalyst and the hydroxy aromatic compound at a moderate temperature and subsequently adding the chlorinated hydrocarbon to the re action mixture at a rate and temperature was to avoid large concentrations of unreacted chlorinated hydrocarbon and excessive foaming.

One conventional process in particular further requires the exercise of very careful temperature control during the alkylation reaction. More particularly, after introducing aluminum chloride at about 150 F., gradual heating by raising the temperature at the rate of one degree per minute up to 350 F. is required until the reaction is complete. By operating in the manner of the present invention, stringent temperature control is not required and the ultmate reaction temperature may be reached in a few minutes as compared to the long period required in the conventional process. Moreover, by avoiding large concentrations of chlorinated hydrocarbon, improved uni-. formity of alkylation results, particularly when it is desired to secure only partial alkylation of the phenol.

The reactants found eminently suitable in the process of this invention include a phenolic body, a chlorinated long-chain hydrocarbon, and a Friedel-Crafts catalyst. Generally, the phenolic body may be any suitable com mercial grade. Similarly, the Friedel-Crafts catalyst, for example, aluminum chloride, may be any commercial grade of the anhydrous material.

The chlorinated long-chain hydrocarbons found eminently suitable in the process of the present invention include chlorinated hydrocarbons having from about 12 to about 30 carbon atoms per molecule and a chlorine content of from about 15 to about 45% of chlorine by weight of the chlorinated hydrocarbon. Included in this class are the paraffinic hydrocarbon waxes and oils of the aforesaid carbon chain lengths. and chlorine contents.

The chlorinated hydrocarbons of the foregoing description may be obtained by chlorinating a hydrocarbon mixture consisting essentially of parafiinic hydrocarbons ICC having from about 12 to about 30 carbon atoms in their molecule. Conventional chlorination techniques may be employed in which chlorine is bubbled through the hydrocarbon mixture until the desired percentage of chlorine has been absorbed. Preferably, the original hydrocarbon should contain no more than minor amounts of aliphatic unsaturation.

The degree of chlorination is important since it is by this means that the number of aromatic hydroxy nuclei introduced into the hydrocarbon chain is determined. By this means, the flexibility of products subsequently made With this material as an intermediate may be controlled. For example, the higher the degree of chlorination, the less the degree of flexibility of such products. The converse of this is similarly true.

The hydroxy aromatic compounds, preferably phenolic bodies Which may be alkylated in accordance with the process of this invention, include phenol, and monosubstituted alkyl phenols, for example, methyl, ethyl, propyl, etc. substituted phenols, mono-halogenated phenols and mono-alkoxy phenols such as methoxy, ethoxy, etc. phenols.

In carrying out the reaction, a FriedeLCrafts catalyst is added to hot phenol, or, alternatively, hot phenol is added to a Friedel-Crafts catalyst, at a moderate temperature of from about 50 to about C., and the chlorinated hydrocarbon added to this mixture at a rate and temperature at which large concentrations of the unreacted chlorinated hydrocarbon and excessive foaming attendant prior processes are eliminated. The temperature maintained during the second phase of the reaction, more specifically during chlorinated hydrocarbon addition, may range from about to about 200 C. with a range of from about to C. being preferred.

Contrary to conventional methods, by following the conditions herein disclosed, the present reaction may be carried out without employing critical temperature control. While it is not desired to be limited to a specific theory of invention, it is believed that the reaction between the phenol and aluminum chloride proceeds to form aluminum monochloride diphenoxide or a mixture of aluminum chloride and phenoxide approximating this composition. Subsequently, the chlorinated hydrocarbon may be added and the temperature raised to the reaction stage, without the degree by degree control required in conventional processes, and the reaction continued until the evolution of hydrogen chloride ceases. Thereafter, product recovery and catalyst removal may be by any suitable means.

In carrying out the present reaction, the proportions of reactants employed can be varied widely. For example, when mono-alkylation is desired, the quantity of the hydroxy aromatic compound which may be employed may range from about 10 mols per chlorine atom, in the chlorinated hydrocarbon, to as little as 0.33 mol per chlorine atom in the chlorinated hydrocarbon when a trialkylated phenol is desired. When the alkylated products are to be employed as intermediates for condensation with other ingredients, for example, aldehydes or other methylene-containing compounds, to form resinous products, they may be prepared by having the reactants present in such proportions that the chlorine-to-phenol ratio is from 0.1 atom of chlorine per mol of phenol to 2.0 atoms of chlorine per mol of phenol. In those cases where excess phenol remains in the alkylation mixture, the excess phenol can be separated from the alkylated product by simple vacuum or steam distillation.

Generally, the proportion of catalyst employed may range from about 0.5 to about 10 percent, by weight, based on the weight of the chlorinated hydrocarbon. A preferred range for the catalyst is from about 2 to about 5 percent, by weight, of the chlorinated hydrocarbon.

The conditions governing the reaction of this invention may be varied within certain limits. For example, reaction temperatures employed in the process may range from about 100 to about 200 C. with a preferred operating temperature being in the range of from about invention, the following examples are given by way of illustration and not by way of limitation. All parts and percentages are by weight.

Example 1 A chlorinated hydrocarbon was prepared by heating 500 parts of a scale wax having a melting point of 124 to 126 F. and an average chain length of about 25 carbon atoms by bubbling chlorine through the hydrocarbon, to 88 C., and chlorination initiated with the aid of ultraviolet light. The heating means were then removed and the chlorine rate adjusted so that a temperature of between 89 and about 93 C. was maintained. Chlorination was continued for approximately three hours or until approximately 25 percent, by weight of chlorine, had been absorbed. The calculated percentage of chlorine in this product was 25.7 percent as compared to the analyses of two samples showing 25.87 percent and 26.06 percent, respectively. The product was characterized as a chlorinated hydrocarbon having an average of 3.4 chlorine atoms per C25 chain.

16.5 parts of aluminum chloride were added to 448 parts of phenol, heated to between 75 and 80 C. during a one-hour period. This addition caused no significant foaming or heat effects and obviously could have been reduced to a few minutes. The mixture was heated to around 175 C. and approximately 662.5 parts of the above prepared chlorinated hydrocarbon were added over a four-hour period. Since the addition of the chlorinated hydrocarbon had a cooling effect on the reaction mixture, moderate heating was required to maintain a temperature of 175 to 180 C. throughout the addition. Because of this cooling effect, it was obvious that the total reaction time could be reduced to a considerably shorter period than the usual three to eight hours required when all the reactants are added at the beginning of the react-ion as in prior methods. I

After the temperature had dropped below 100 C., 250 parts of distilled water were added to the reaction mixture to hydrolyze the aluminum salts. A .small quantity of ether, stirred into the cold hydrolysis mixture, reduced the viscosity and aided transfer of the products to a continuous ether extractor. After removal of unreacted phenol, approximately 562 parts of an alkylated phenol corresponding to 60.4 percent of the calculated yield were recovered. By calculation and analysis, taking into consideration the recovery of 206 parts of unreacted phenol and the chlorine analysis which indicated that 97 percent of introduced chlorine had reacted, the product was characterized as a 1.8-25 alkylated phenol which is the designation for an alkylated phenol having an average of 1.8 alkyl groups per molecule and which further indicates that the hydrocarbon has been polyarylated to an extent of 25 percent. The ash content of the final product was 0.003 percent.

Example 2 In a manner similar to that of Example 1, 301 parts of phenol, heated to 50 C., were added to 16.5 parts of aluminum chloride in a two-minute period. Rapid addition of the phenol caused no significant foaming or heat effects. External heating for fifteen minutes raised the temperature to 95 C. and addition of 660 parts of the chlorinated hydrocarbon employed in Example 1 was started. During the next hour, 400 parts of chlorinated hydrocarbon were added and the temperature raised to 175 C. where it was maintained. Addition of the chlorinated hydrocarbon required an additional 40 minutes, after which hydrochloride evolution substantially ceased. The elapsed time for mixing phenol and aluminum chloride was 3.25 hours.

The mixture was cooled, hydrolyzed with 250 parts of distilled water, refluxed for fifteen minutes and transferred to an ether extractor. After removal of unreacted phenol by distillation, alkylated product corresponding to 622 parts or percent of the calculated yield was recovered. Taking into consideration the recovered phenol, about 32.5 percent, and the estimated residual chloride which was about 4 percent, the alkylated product was characterized as 21-25. The ash content of the product after a single extraction was 0.002 percent.

Alkylation of hydroxy aromatic compounds in accordance with the present process results in numerous advantages over the processes conventionally employed. Among these advantages are the elimination of excessive foaming, and its accompanying difiiculties. Another advantage is the production of a more uniform product. Additionally, the process, by virtue of improved control,

permits more efiicient utilization of equipment through Still anlarger charges and/or shorter reaction times. other advantage results from the elimination of excess foaming, namely, the time required to reach reaction temperature is shortened to such an extent that large economies are thereby effected.

The products of the present invention have a large field of utility. For example, they may be used as pour point depressants in lubricating oils and as intermediates in the preparation of various resins and varnishes, etc.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A method of preparing alkylated hydroxy aromatic compounds which comprises the sequential steps of (1) mixing together a phenol having at least one unsubstituted nuclear carbon atom and a small quantity of a Friedel- Crafts catalyst, (2) adding to the resulting mixture a longchain chlorinated'hydrocarbon having from 12 to 30 carbon atoms and containing from about 15 to 45%, by weight of chlorine, at a rate which avoids large concentrations of unreacted chlorinated hydrocarbon while maintaining a reaction temperature of from about to about 200 C., and (3) recovering an alkylated phenol.

2. A method of preparing alkylated hydroxy aromatic compounds which comprises the sequential steps of (1) mixing together a phenol having at least one unsubstituted nuclear carbon atom and a small quantity of a Friedel- Crafts catalyst, (2) adding to the resulting mixture a longchain chlorinated aliphatic hydrocarbon having from 12 to 30 carbon atoms and containing from about 15 to 45 percent, by weight of chlorine, at a rate which avoids large concentrations of unreacted chlorinated hydrocarbon, while maintaining a reaction temperature of from about 100 to about'200 C. until the evolution of hydrogen chloride has substantially ceased, (3) washing the reaction mixture whereby residual catalyst is hydrolyzed, and (4) recovering an alkylated phenol.

3. A. method of preparing alkylated hydroxy aromatic compounds which comprises the sequential steps of 1) mixing together a phenol having at least one unsubstituted nuclear carbon atom and a Friedel-Crafts catalyst, (2) adding. a long-chain chlorinated aliphatic hydrocarbon having from 12 to 30 carbon atoms and containing from about 15 to 45 percent, by weight of chlorine, at a rate which avoids large concentrations of unreacted chlorinated hydrocarbon while maintaining a reaction temperature of from about 100 to about 200 C. until the evolution of hydrogen chloride has substantially ceased, the quantity of said catalyst corresponding to from about 0.5 to about 10 percent, by weight of said chlorinated hydrocarbon, (3) allowing the reaction mixture to cool, (4) washing the reaction mixture whereby residual catalyst is hydrolyzed and (5) recovering an alkylated phenol from the reaction mixture by extraction.

4. A method of preparing alkylated hydroxy aromatic compounds which comprises the sequential steps of (1) mixing together a phenol having at least one unsubstituted nuclear carbon atom and aluminum chloride, (2) adding a long-chain chlorinated aliphatic hydrocarbon having from 12 to 30 carbon atoms and containing from about 15 to 45 percent, by weight of chlorine, at a rate which avoids large concentrations of unreacted chlorinated hydrocarbon while maintaining a reaction temperature of from 100 to about 200 C. until the evolution of hydrogen chloride has substantially ceased, the quantity of said catalyst corresponding to from about 0.5 to percent, by weight of said chlorinated hydrocarbon, (3) allowing the reaction mixture to cool, (4) washing the reaction mixture whereby the residual catalyst is hydrolyzed and (5) recovering an alkylated phenol from the reaction mixture by extraction.

5. A method of preparing alkylated phenols which comprises the sequential steps of (1) mixing together a phenol having at least one unsubstituted nuclear carbon atom and a small quantity of a Friedel-Crafts catalyst, (2) adding a long-chain chlorinated hydrocarbon having from 12 to 30 carbon atoms and containing from about 15 to 45 percent, by weight of chlorine, at a rate which avoids large concentrations of unreacted chlorinated hydrocarbon while maintaining a reaction temperature of from about 100 to about 200 C. until the evolution of hydrogen chloride has substantially ceased, (3) allowing the reaction mixture to cool, (4) washing the reaction mixture whereby residual catalyst is hydrolyzed, and (5) recovering an alkylated phenol from the reaction mixture by extraction.

6. A method of preparing alkylated phenols which comprises the sequential steps of (l) mixing together a phenol having at least one unsubstituted nuclear carbon atom and aluminum chloride, (2) adding a long-chain chlorinated aliphatic hydrocarbon having from about 12 to carbon atoms and containing from about 15 to 45 percent, by weight of chlorine, at a rate which avoids large concentrations of unreacted chlorinated hydrocarbon while maintaining a reaction temperature of from 100 to about 200 C. until the evolution of hydrogen chloride has substantially ceased, the quantity of said catalyst corresponding to from 0.5 to about 10 percent, by weight of said chlorinated hydrocarbon, (3) allowing the reaction mixture to cool, (4) washing the reaction mixture whereby the catalyst is hydrolyzed, and (5) recovering an alkylated phenol from the reaction mixture by extraction.

7. A method of preparing an alkylated phenol which comprises the sequential steps of (l) mixing together a phenol having at least one unsubstituted nuclear carbon atom and aluminum chloride, (2) adding a long-chain chlorinated aliphatic hydrocarbon having from about 12 to 30 carbon atoms and containing from about 15 to percent, by weight of chlorine, at a rate which avoids large concentrations of unreacted chlorinated hydrocarbon while maintaining a reaction temperature of from to about 200 C. until the evolution of hydrogen chloride has substantially ceased, the quantity of said catalyst corresponding to from 0.5 to about 10 percent, by weight of said chlorinated hydrocarbon, (3) allowing the reaction mixture to cool, (4) washing the reaction mixture whereby residual catalyst is hydrolyzed, and (5) recovering an alkylated phenol from the reaction mixture by ether extraction.

8. A method of preparing an alkylated phenol which comprises the sequential steps of 1) mixing together a phenol having at least one unsubstituted nuclear carbon atom and aluminum chloride, (2) adding a long-chain chlorinated aliphatic hydrocarbon having from about 12 to 30 carbon atoms and containing from about 15 to 45 percent, by weight of chlorine, at a rate which avoids large concentrations of unreacted chlorinated hydrocarbon while maintaining a reaction temperature of from 100 to about 200 C. until evolution of hydrogen chloride has substantially ceased, the quantity of said catalyst corresponding to from 0.5 to about 10 percent, by weight of said chlorinated hydrocarbon, and the proportion of phenol to chlorinated hydrocarbon adjusted so that the chlorine to phenol ratio is from 0.1 atom of chlorine per mol of phenol to 2.0 atoms of chlorine per mol of phenol, (3) allowing the reaction mixture to cool, (4) washing the reaction mixture whereby residual catalyst is hydrolyzed, and (5) recovering an alkylated phenol from the reaction mixture by ether extraction.

9. The method of claim 7 wherein the chlorinated aliphatic hydrocarbon is a parafiinic hydrocarbon wax.

10. The method of claim 7 wherein the chlorinated aliphatic hydrocarbon is a paraflinic hydrocarbon oil.

Putnam et al. May 5, 1936 Reiff Feb. 27, 1940 

2. A METHOD OF PREPARING ALKYLATED HYDROXY AROMATIC COMPOUNDS WHICH COMPRISES THE SEQUENTIAL STEPS OF (1) MIXING TOGETHER A PHENOL HAVING AT LEAST ONE UNSUBSTITUTED NUCLEAR CARBON ATOM AND A SMALL QUANTITY OF A FRIEDELCRAFTS CATALYST, (2) ADDING TO THE RESULTING MIXTURE A LONGCHAIN CHLORINATED ALIPHATIC HYDROCARBON HAVING FROM 12 TO 30 CARBON ATOMS AND CONTAINING FROM ABOUT 15 TO 45 PERCENT, BY WEIGHT OF CHLORINE, AT A RATE WHICH AVOIDS LARGE CONCENTRATIONS OF UNREACTED CHLORINATED HYDROCARBON,WHILE MAINTAINING A REACTION TEMPERATURE OF FROM ABOUT 100* TO ABOUT 200*C. UNTIL THE EVOLUTION OF HYDROGEN CHLORIDE HAS SUBSTANTIALLY CEASED, (3) WASHING THE REACTION MIXTURE WHEREBY RESIDUAL CATALYST IS HYDROLYZED, AND (4) RECOVERING AN ALKYLATED PHENOL. 